1. Field of the Invention
Priority is claimed on Japanese Patent application No. 2004-336345, filed Nov. 19, 2004, No. 2004-343160, filed Nov. 26, 2004, and No. 2004-343161, filed Nov. 26, 2004, the contents of which are incorporated herein by reference.
The present invention relates to a reflection type projecting screen, and more particularly, to a reflection type projecting screen capable of being preferably used in a front projector system or the like which reflects projection light projected from a cine-projector, a projector, or the like which is positioned at a viewing side, in order to view an image. In addition, the present invention relates to a front projector system using a reflection type projecting screen. Furthermore, the present invention relates to a multi-vision projector system, and more particularly, to a multi-vision projector system in which it is possible for a plurality of viewers to appreciate images different from one another, together with sounds which correspond to the respective images.
2. Description of the Related Art
In the case of projecting an image such as a dynamic image, a static image, or the like on a screen by a projector such as a cine-projector, a projector, or the like, in order to appreciate the image in a conventional reflection type projecting screen, there is a problem in which contrast becomes poor in the image produced by the projection light, inasmuch as outside light is reflected on the screen in a bright room. In order to solve the above-mentioned problem, a proposal has been made as regards a reflection type projecting screen having improved reflection properties.
More specifically, a description is made in Japanese Patent Application Unexamined Publication No. 1994-148747 (Pages 2 to 3) about a projecting screen having a metal thin layer and a mat layer with an organic spherical filler. The projecting screen has reflection brightness with respect to white light that is not less than 10% and has a half-value angle with respect to the reflection brightness that is not less than 30 degrees.
A description is made in Japanese Patent Application Unexamined Publication No. 2003-287818 (Pages 5 to 16, FIGS. 1, 6, and 7) about a reflection type screen having a bead diffusion layer, a cholesteric liquid crystal (CLC) layer, and a shielding layer in that order from a light source (projector). Furthermore, a description is made in Japanese Patent Application Unexamined Publication No. 2003-287818 about a reflection type screen having a CLC layer, a substrate forming concavity and convexity in which the CLC layer forms a diffuse reflection layer, and a shielding layer in that order from a light source. In addition, a description is made in Japanese Patent Application Unexamined Publication No. 2003-287818 about a reflection type screen having a CLC layer, a substrate forming concavity and convexity in which the CLC layer forms a corner cube structure, and a shielding layer in that order from a light source.
In addition, a description is made in Japanese Patent Application Unexamined Publication No. 2003-195788 (Pages 5 to 10, FIGS. 1 and 15) about a display device having a corner cube array comprising a color filter, a diffuse type liquid crystal layer capable of switching between reflection and diffusion, and a corner cube reflector in that order from a light source. The corner cube array realizes only retro-reflection by making the diffuse type liquid crystal layer switch between reflection and diffusion and selectively realizes a state of cutting off light emitted from the light source and a state of diffusively reflecting light emitted from the light source.
Furthermore, a description is made in Japanese Patent Application Unexamined Publication No. 1993-150368 (Pages 2 to 4, FIGS. 1 to 5) about a reflection type screen having a retro-reflection property that comprises a corner cube mirror having two reflection surfaces each of which is formed into a concave surface. The reflection type screen diffuses the light reflected by each of the concave surfaces and has a reflecting directivity in which the light width is narrow in a vertical direction and is wide in a horizontal direction.
However, the above-mentioned conventional reflection type screens have the following problems.
In the art described in Japanese Patent Application Unexamined Publication No. 1994-148747, it is not stated that utilization efficiency of light is not sufficiently improved, although the reflection brightness is not less than 10% and is slightly improved in comparison to the prior art. As a result, there is a problem in which it is necessary to have a light source having high power.
In the art described in Japanese Patent Application Unexamined Publication No. 2003-287818, it is necessary to control the layer thickness and the orientation of the CLC layer over the screen, although it is possible to improve the utilization efficiency of light by using the CLC layer. Therefore, there is a problem in which the screen becomes expensive to produce. As result, it is difficult to easily apply the art described in Japanese Patent Application Unexamined Publication No. 2003-287818 to a large-scale projecting screen.
In the art described in Japanese Patent Application Unexamined Publication No. 2003-195788, a description is made about the display device capable of switching between retro-reflection and diffuse reflection by using the corner cube reflector and the diffuse type liquid crystal layer. In the case of being employed in the reflection type projecting screen, there is a possibility that the utilization efficiency of light can be improved. However, there is a problem in which the reflection type projecting screen becomes very expensive to produce, inasmuch as the diffuse type liquid crystal layer is located on the back surface of the corner cube reflector and it is necessary to electrically control the diffuse type liquid crystal layer.
Although it is possible to reflect the light having a comparative high directivity with respect to an incident direction by forming the concave surface on the corner cube mirror in the art described in Japanese Patent Application Unexamined Publication No. 1993-150368, the reflection type screen becomes very expensive to produce inasmuch as it is necessary to form a correct concave shape on the corner cube mirror at great expense in both time and effort.
In addition, there is a problem in which it is impossible to obtain high image quality inasmuch as the image becomes irregular, in the case where an error becomes large with respect to the formation of the concave surface.
Taking the above-mentioned problems into consideration, it is an object of the present invention to provide a reflection type projecting screen having a simple structure that is capable of reducing the effect of outside light and improving the utilization efficiency of light.
With respect to the front projector system, a proposal is made about a projecting screen capable of improving a reflection property in order to solve the problem in which the contrast becomes poor in the image produced on the basis of the projection light because the outside light is reflected on the screen in a bright room.
More specifically, a description is made in Japanese Patent Application Unexamined Publication No. 1993-273651 (Pages 2 to 3, FIGS. 1 and 2) about a projecting reflection type screen having a plurality of beads each of which has an approximate spherical shape and whose refractive indexes are different from one another. The beads are positioned on a screen substrate forming a reflective layer on its hemispherical surface opposite to the light source.
In addition, a description is made in Japanese Patent Application Unexamined Publication No. 1999-202417 (Pages 2 to 6, FIG. 1) about a hologram screen having a hologram element and a light diffuse element. The hologram element has a function of diffracting the projection light which is projected from the projector. The light diffuse element has a diffuse angle which is not less than 5 degrees.
In general, it is known that one projector projects an image on one screen in a conventional projector system, and a plurality of viewers are positioned within a predetermined angle range with respect to the projecting direction, in order to appreciate the image projected on the screen. Furthermore, a multi-vision system is known in which a plurality of projectors project images on one screen while changing the projecting regions of each of the images. It is possible for each viewer to appreciate each image in the multi-vision system.
However, the above-mentioned conventional projector systems have the following problems.
In the case where one projector projects the image on one screen, there is a problem in which equipment such as a screen and a projection room becomes large and the utilization efficiency becomes poor, because the entire screen is occupied even if there are not many viewers.
Although it is possible to improve the efficiency with respect to the equipment because a plurality of images are projected on one screen in the multi-vision system, there is a problem in which other images obstruct viewing, in the case of projecting unrelated images. In addition, it is problematic to project images of a confidential or delicate nature such as explanatory materials used in a conference, because the viewers positioned before the screen can view all of the images.
On the other hand, a projector system has not been known which shares one screen between the images by projecting the images on a common region of one screen, in order to appreciate images different from one another, in a plurality of viewing groups.
More particularly, the art described in Japanese Patent Application Unexamined Publication No. 1993-273651 makes the refractive index vary in each bead, in order to change the directivity of reflection light, in the case of constructing such a projector system. As a result, it is difficult to freely change the directivity of reflection light and it is difficult to strictly control the reflected direction and diffuse range in accordance with the incident angle of the image. In addition, there is a problem in which the diffuse range becomes wide and the reflectivity is reduced on the basis of diffusion between the beads. As a result, there is a problem in which it is difficult to strictly divide the image into a plurality of image components and degradation occurs in the image quality, in the case of inputting a plurality of images.
Although it is possible to output light having directivity with respect to a specific direction when the light is inputted from a specific incident direction, because the art described in Japanese Patent Application Unexamined Publication No. 1999-202417 uses diffractive light obtained by a hologram element, and it is necessary to have a high power light source because the utilization efficiency of light is poor. Furthermore, there is a problem in which flare light easily occurs. In addition, there is problem in which it is difficult to make the layout of the projectors and the screen in agreement with locations, inasmuch as the input and the output directions are limited to directions which are strictly determined on manufacturing the hologram element. In addition, it is difficult to manufacture a large-scale screen because of using the hologram element.
Taking the above-mentioned problems into consideration, it is an object of the present invention to provide a front projector system capable of projecting an image in a specific region based on an incident direction without being obstructed by outside light and other images, by projecting the images on one screen while changing the incident direction. It is another object of the present invention to provide a front projector system capable of effectively using one screen in the case of projecting a plurality of images and capable of easily establishing a viewing region with respect to the screen.
In a projector system which projects an image such as a dynamic image, a static image, or the like on a screen by a projector such as a cine-projector, a projector, or the like, on viewing the image, it is known that one projector projects an image on one screen, and a plurality of viewers are positioned within a predetermined angle range with respect to the projecting direction, in order to view the image projected on the screen. Furthermore, a multi-vision projector system is known in which a plurality of projectors project images on the projecting regions which are defined on one screen, in order to view the images.
More specifically, a description is made in Japanese Patent Application Unexamined Publication No. 2000-3182 (Pages 3 to 5, FIGS. 1, 2, and 4) about a projector system which forms an internal space of an attraction hall that is for projecting a three-dimensional image on the screen and a projector system which provides a visual effect such as the same image to viewers each sitting on a chair. Furthermore, a description is made in Japanese Patent Application Unexamined Publication No. 2000-3182 (Pages 3 to 5, FIGS. 1, 2, and 4) about a sound system capable of playing sounds which are different from one another in synchronization with the images.
However, the above-mentioned conventional projector system has the following problem.
In the case where one projector projects the image on one screen, there is a problem in which equipment such as a screen and a projection room becomes large and the utilization efficiency becomes poor, because the entire screen is occupied even if there are not many viewers.
Although it is possible to improve the utilization efficiency with respect to the equipment because a plurality of images are projected on one screen in the multi-vision system, there is a problem in which other images obstruct viewing, in the case of projecting unrelated images.
Although it is possible to expect an effect in which it is easy to selectively view the image corresponding to the sound because it is possible for each viewer to listen to a different sound, in the case of applying the art described in Japanese Patent Application Unexamined Publication No. 2000-3182 to the multi-vision system, there is a problem in which the view is visually obstructed because other images come into view. For example, it is problematic to project images of a confidential or delicate nature such as explanatory materials used in a conference, because the viewers positioned before the screen can view all of the images.
On the other hand, a projector system has not been known which shares one screen between the images by projecting the images on a common region of one screen, in order to appreciate images different from one another, in a plurality of viewing groups.
Taking the above-mentioned problems into consideration, it is an object of the present invention to provide a multi-vision projector system capable of displaying an image and playing a sound related to the image in each viewing region without being obstructed by images and other sounds even if a plurality of images are projected on a screen, in order to effectively use the screen and to independently display the image and playing the sound in each viewing region.